M2M technologies refer to all technologies and methods for establishing connections between machines. The concept of M2M appeared early in the 1990s, but remained in a theoretical stage. With the development of mobile communication technologies, it was after the year 2000 that network connections between machines and devices became possible via mobile communication technologies. Around the year 2002, M2M services appeared on the market and developed rapidly in the years that followed to become an attention focus of many communication equipment manufacturers and telecommunication operators. In addition, the number of machines all over the world far exceeds the number of human beings currently. Therefore, it is expected that M2M technologies have good market prospects.
Researches on M2M communication application scenarios have shown that it has potential market prospects to provide M2M communication on mobile networks. In addition, the competition of the telecommunication market is becoming increasingly fierce, fees are decreasing, profits of operators are declining constantly and the human-based communication market is becoming increasingly saturated. Therefore, M2M communication is a brand new development opportunity for the operators.
However, existing mobile communication networks are mainly designed for Human to Human (H2H) communication and the optimization for M2M communication and H2H communication is deficient. Therefore, many new requirements have been raised by M2M services for existing mobile communication systems. In order to enhance the competitiveness of mobile networks in this aspect, it is necessary to optimize the existing mobile communication networks so as to support M2M communication more efficiently. In addition, how to provide M2M communication services by operators at low costs is a key to successful M2M communication deployment.
Based on the analysis above, it is necessary to study solutions for mobile networks to support M2M communication. The solutions must be able to utilize existing networks to the utmost extent while reducing the influence of a large amount of M2M communication to the networks and reducing the complexity of operation and maintenance.
In the related art, in order to utilize existing mobile network resources efficiently, the 3rd Generation Partnership Project (3GPP) has put forward Machine Type Communication (MTC), i.e. services using M2M communication and Machine to Man communication, and the service range far exceeds that of conventional H2H communication. In addition, there are great differences between MTC and existing H2H communication mode in aspects such as access control, charging, safety, Quality of Service (QoS) and service modes etc.
FIG. 1 is a schematic diagram of a framework of a 3GPP Evolved Packet System (EPS). It can be seen from FIG. 1 that the EPS comprises: a Radio Access Network (RAN) and a core network, wherein the RAN may specifically refer to a Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), an Evolved UTRAN (E-UTRAN), or a Global System for Mobile Communications (GSM)/Enhanced Data rates for GSM Evolution (EDGE) Radio Access Network (GERAN) etc. In the E-UTRAN, an Evolved Node B (eNB) is comprised. For the composition of the core network, in an Evolved Packet Core (EPC) network, i.e. when the RAN is an E-UTRAN, the core network comprises: network elements such as a Mobility Management Entity (MME), a Serving Gateway (S-GW) and a Packet Data Network (PDN) Gateway (P-GW); and in a General Packet Radio Service (GPRS), i.e. when a RAN is an UTRAN or a GERAN, the core network comprises: network elements such as a Serving GPRS Support Node (SGSN) etc.
To realize an MTC system, one of the basic requirements for the MTC system is to maintain connections of a large number of MTC devices efficiently. In other words, the MTC system must provide a mechanism for maintaining connections of a large number of MTC devices efficiently. Therefore, factors of the following three aspects need to be considered: 1. effectiveness; 2. connection maintainability; 3. a large number of MTC devices. Only the second aspect is clear in current researches, i.e. an “always on” state is maintained; for the third aspect, the meaning of “a large number” is unclear, i.e. the quantity of “a large number” is unclear; and for the first aspect, the definition of effectiveness is also unclear. Although the definition of effectiveness is unclear, it can be learned from discussions of previous 3GPP conferences that the requirement of effectiveness is mainly directed at the problem of how to maintain related resources by a network device effectively when a large number of devices are in the “always on” state.
Based on the network framework as shown in FIG. 1, FIG. 2 is a schematic diagram of a framework of an MTC system in 3GPP. As shown in FIG. 2, in the MTC system, links among a UE, an RAN, a Gateway GPRS support Node (GGSN)/P-GW/Evolved Packet Data Gateway (ePDG) and an MTC server need to be maintained, wherein a dashed line “------ ” indicates the connection of a control plane and a solid line “_”indicates the connection of a user plane in FIG. 2.
In a Long Term Evolution (LTE) network, a UE is in the “always on” state after being attached to the network until the UE is detached, and a network device needs to maintain related information such as context information etc. of the UE in the “always on” state. If a large number of devices are in the “always on” state, then a large amount of context information needs to be maintained inevitably, and thereby a large number of network resources can be occupied. However, there is no technical solution for managing network resources effectively while reducing the occupation of the network resources as much as possible currently.
In addition, when there is no data transmission between the UE and the network device, a radio link bearer may be released or detachment may be performed so as to reduce the occupation to radio resources. However, in related art, after the radio link bearer is released, there is no technical solution for reestablishing a radio connection rapidly when data needs to be transmitted.